1. Field of the Invention
The present invention relates to a string-attached cap in which one end of an elongated coupling member is connected to a cap.
The present application is based on Japanese Patent Application No. Hei. 11-301567, which is incorporated herein by reference.
2. Description of the Related Art
In a fuel tank of an automobile, a cap is, in general, connected to the fuel tank by means of an elongated coupling member to prevent the loss of the cap during re-fueling. As such string-attached caps, those disclosed in, for example, Japanese Patent Publications No. Hei. 3-295723 and Sho. 62-173321 or the like are known.
FIG. 21 shows the string-attached cap disclosed in Japanese Patent Publication No. Hei. 3-295723, and in this string-attached cap one end of a coupling member 13 is connected to a handle portion 5a of a cap 5 by means of a fixing member 1.
However, with such a conventional string-attached cap, since the coupling member 3 is connected to the cap 5 by means of the fixing member 1, there has been a problem in that the number of component parts increases, requiring a large number of steps in assembly in accordance with a structure of the fixing member.
A string-attached cap disclosed in U.S. Pat. No. 5,720,409 was developed to overcome these problems.
FIG. 22 shows this string-attached cap. This string-attached cap is arranged such that a coupling member 13, which is formed of flexible resin, has a ring part 13a formed integrally at one end thereof, and an engaging part 13b formed integrally with the inner periphery of the ring part 13a is rotatably engaged in an annular groove lid formed in the outer periphery of a cap 11.
With this string-attached cap, since the ring part 13a of the coupling member 13 is inserted and fitted in the annular groove 11d formed in the cap 11, the coupling member 13 does not constitute an obstruction when the cap 11 is turned while gripping a handle portion 11b.
In addition, when the cap 11 is inserted into the ring portion 13a of the coupling member 13, the engaging part 13b at the inner periphery of the ring part 13a is elastically deformed, and if the cap 11 in this state is inserted up to the annular groove 11d, the engaging part 13b is restored to its original state and is engaged in the annular groove 11d, so that the number of assembling steps can be substantially reduced as compared with the conventional art.
However, with the above-described conventional string-attached cap, since a countermeasure against static electricity is not provided, at the time of removing the cap from the fuel tank, there is the risk of occurrence of spark discharge as static electricity charged in the human body is discharged through fingers and the like which came into contact with the cap. To resolve this spark charge, it is conceivable to form the string-attached cap of, for example, an electroconductive material and discharge the static electricity to the vehicle side. The electroconductive material can be constituted by, for example, an electroconductive resin; however, in the compounding of the electroconductive material which is mixed into it, there is the possibility that the following problem can be occur.
Namely, if the amount of the electroconductive material mixed is extremely small, electric conduction is lowered, and the discharge of static electricity does not take place completely, so that there are cases where the remaining static electricity causes secondary spark discharge. On the other hand, if the amount of the electroconductive material mixed is extremely large, although electric conduction is enhanced, there can arise cases in which the moment the human body comes into contact with the cap, the human body receives a large shock.